Combined sewers continue to overflow in Milwaukee, Shorewood
Combined sanitary and storm sewers in central Milwaukee and eastern Shorewood continued overflowing to local rivers and Lake Michigan Monday night in the wake of the weekend's heavy storms, which dropped nearly 4 inches of rain on some areas, a Milwaukee Metropolitan Sewerage District official said.
Light rain was forecast Monday evening, so the district expected to continue blending partly treated sewage and fully treated wastewater at its Jones Island treatment plant, district Executive Director Kevin Shafer said. Blending is done to boost treatment capacity at Jones Island and enable workers to pump wastewater out of the deep tunnel.
At 6:30 p.m. Monday, the deep tunnel was at 88% capacity and a separate segment, known as the Northwest Side deep tunnel, was full.
Pumps were draining the tunnel at a rate of 150 million gallons a day on Monday while flows from communities with separate sanitary sewers were spilling wastewater into the tunnel at a rate of more than 85 million gallons a day.
Both blending and combined sewer overflows started Sunday in an attempt to prevent basement backups in the metropolitan area served by the district and to prevent overflows of separate sanitary sewers to urban streams.
Brown Deer, Mequon, Elm Grove and the Milwaukee Metropolitan Sewerage District reported sanitary sewer overflows during Sunday's heavy rain, said Jim Fratrick, regional watershed coordinator for the state Department of Natural Resources in Milwaukee.
One of the district's regional sewers near N. Green Tree Road and the Milwaukee River discharged an estimated 620,000 gallons of sewage to the river on Sunday, a district official said. The sewer was overwhelmed by excessive flows that exceeded its design capacity. The overflow there ended late Sunday.